Why not open the movie here in the US first, then branch out to other countries...

Because last time Paramount and JJ were highly criticised that ST 2009 was somehow a failure - or, at least, a disappointment - at the international box office. So the marketing people created a (successful) strategy that saw the international box offices do extremely well.

OR open it worldwide on the same day.

And then you can't tour the actors around for all the free publicity at the red carpet openings.

Imminent Anterior Aneurysm wrote:

My opinion of the better video sales for ID over IM3; more people saw IM3 in the theater and felt 'finished' with it while hordes who missed ID in theaters are now catching up. [/speculative theory]

Ditto "Nemesis". It created new sales records for the day of release on DVD, IIRC.